Concrete mixing machine



Jan. 26, 1932. I K. PIEHLER 1,842,879

' CONCRETE MIXING MACHINE FilecLDec. 5. 1929 Patented Jan. 26, 1932V ATENT oFFreE KARL PIEHLEB, OFLEIPZIG, GERMANY CONCRETE MIXING MACHINE Application filed December 5, 1929, Serial No. 411,887, and in Germany December 12, 1928.

The invention relates to concrete mixing machines of the type in which the drum, which rotates round a horizontal axis, possesses on the inside cup-like scoops which pick up the mixing material in batches in the under part or" the drum and throw it back at the top of the drum towards the interior of the latter, so that a discharging means, projecting into the interior ot the drum but 1 not rotating therewith, can be charged from the top. In concrete mixing machines of this type each scoop has hitherto possessed a double bottom or a bottom inclined at differentY of the type referred to in such a mannerY that the drum can'always be driven in the same direction, bothfor mixing and dis:

charging, reversible driving motors, reversing gears and the like' being thus rendered unnecessary. In conjunction herewith it becomes possible, in spite of. low structural height of the machine, and whilst avoiding charging elevators, high ramp ways or lowering of the machine, to charge the latter with material to be mixed from the side by means of ordinary transport vehicles, and in spite of the low structural height, a Jtransport vehiele level with the bottom of the mixer can be loaded.

In this connection the invention renders itV possible, during the mixing and discharging of one charge, to prepare the next charge with correctly proportioned'raw materials in such a manner that it canA at oncel be fed into the drum as a single batch, and the drum again reversed for mixing after emptying out the preceding charge.

According to the invention there projects 5o into the rotating drum up to the immediate vicinity of the discharge position of the scoops, a discharge slide whichdoes not rotate with the drum and which can be so adjusted that the material thrown onto it from the scoops is eitherguided back into the drum or outwards into the transport means. The sildeean thus be used in conjunction with the ejectlng action oi the scoops for mixing or emptying the material. As the slide projects with its receiving end into the highest part of theV interior of the drum, its discharge end, located outside the drum, can be positioned at such a height that in spite of the low structural height of the machine, a transport vehicle level with the bottom of the latter can be driven under it.

In addition, on the front side of the drum away from the discharge end of the slide and in the lower part of the former, a gauging or filling container is provided, which renders it possible to prepare the next charge whilst the drum is rotating, by filling in the materials by. means or" ordinary wheelbarrows and the like, thus dispensing with special hoisting means and the like. At most a small ramp of the most simple construction is necessary, if the mixing material is to be tipped into the filling hopper. They latter is itself adapted to be tipped Vvor is provided with a bottom trap, which renders; it possible for a prepared charge to fall immediately into the drum when the preceding charge is emptied out and the slide has returned to the mixing position. In thenew machine the drum can run continuously and always in the same direction, during mixing, emptying or filling.

`A concrete mixing machine according to the invention is shown by way of example in the accompanying drawings, of which Fig. 1 is a side view;

Fig. l2 a medial vertical section on the line II-II of Fig. l; i

Fig. 3 a side view of the lower end adjusted for mixing;

Fig. 4 is a-fdetail of a filling hopper, provided with adjustable transverse partitions; and

Fig. 5 is a side view of the lower end of the discharge'slide, at which the adjustment'of the slide to mixing or emptying through a trap controlling an opening in the bottom is effected. l D

The concrete mixing machine shown 1n tht (hitflip hat :i lieveling sind 1l4 imining on wheels, on which 1S mounted a drum 2, cylindrical in the middle and of truncated cone shape at both sides. The drum rests on'rollers 3 and is rotated by means of a motor, not shown in the drawings, mounted in the casing 4 through a gearing 5 and Chain drive 6, always in the direction of the arrow 7 (Fig. 1). The casing 4 carries at the top a water tank 8, from which the necessary water for preparing the concrete is delivered to the drum.

The drum 2 is provided on its inner periphery with sloping blades 9, which, in conj unction with the adj acent walls of the drum, form a series of scoops. When the drum is rotating in the direction of the arrow 7, it takes up in batches the material which it contains by means of the scoops. Vhen the blades have approximately reached the upper end ot' the drum, the material contained in the scoops slides downwards owing to the sloping position of the blade bottoms 9, to fall back into the lower part of the continuously rotating drum. This action of such scoops has already been used for filling the ready mixed material from the top into a transport vehicle standing inside the drum or the like, after it had been previously mixed by a rotation of the drum in the opposite direction to the arrow 7 and by the cooperation of the under surfaces of the blades 9.

In order to render it possible, both during mixing and emptying, to maintain a constant direction of rotation of the drum and simultaneously to permit, even with low structural height of the entire machine, the emptying or the mixed material into a transport vehicle standing on a level with the bottom of the machine. according to the invention, a slide 10 is provided, which has a considerably sloping bottom and is on the whole substantally in the form of a funnel and which extends into the inside of the machine to the immediate vicinity of the scoops. The upper or receiving end widens out in both directions and is adapted to catch the material thrown out of the scoops and to convey it downwards in the direction of the arrow 11 (FigsQ2 and The lower end 12 of the slide projects somewhat beyond the adjacent front wall of the drum 2, but, according to Fig. 2, is at such a height above the ground that a transport container 13-for example, a wheelbarrow or a small tipping through can be passed underneath.

The lower end 12 is designed as a separate part, pivotally mounted at 14, which by means oi a lever 15 and an actuating rod 16 of any suitable kind, can be moved into the position according to Figs. 2 and 3. In the position shown in Fig. 2 the bottom of the part 12 forms a continuation of the bottom ot' the part 10, so that the mixed material thrown out ofthe scoops is immediately ccnvcyed outside the duim and guided m the di I -iu rection ci' tile arrows ll, mi() i le Ve llt t. The position shown in Fig. 2 is thus the emptying position of the slide 10. If, on the other hand, the part 12 is moved into the position according to Fig. 3, it interrupts the bottom of the slide 10. The bottom then forms a deviation surface for the material thrown out of the scoops, by means of which it is continuously conveyed back in the direction of the arrows 11 and 18 (Fig. 3) into the inside of the drum. As long as the slide 10 is in the condition shown in Fig. 3, it cooperates in the mixing of the material, the latter being continuously taken up by the scoops at the bottom thrown on to the slide 10 at the top and again guided back by the latter into the bottom part of the drum. The slide 10 may, if necessary, also be removably or pivotally arranged so that the machine can also be driven in the known manner in two opposite directions of rotation of the drum.

According to Fig. 5 the bottom of the slide 10, immediately inside the adjacent Jfront wall of the drum, is provided with an opening 19, which is closed by a flap 21 pivoted at 20. 0n the other side of the pivot 20, the fiap 21 has an extension 22, which, in the position shown in broken lines in Fig. 5, is capable of closing the lower end of the slide. In this broken line position of the flap 21, 22, the bottom opening 19 is uncovered, so that the material sliding downwards over the bottom of the slide 10 is again returned to the bottom part of the drum in the direction of the arrow 18, under the guid ance of tho flap 21, 22 where it is mixed. Otherwise the material passes oit into the transport vehicle standing underneath. The action of the example shown in Fig. 5 is thus the same as that shown in Figs. 2, 3.

Underneath the slide 10 and covered by the bottom thereof, there is mounted in the bottom part of the drum and not rotating therewith, a measuring or filling container 23. The latter is open at the front and the top and has a sloping bottom 24, 25. The bottom wall 25 is provided with an opening 26, adapted to be closed or opened by a flap 28 pivotally mounted at 27. The control of the flap 28 is effected by a rod 29 of any kind. As the drum 2, for the above mentioned reasons, can be mounted very low, the container 23 is also arranged at such a low height above the ground, that it can be readily charged with the aid of a wheelbarrow 30, for the ruiming up of which, however, a small ramp 31 of the simplest possible type is at most necessary. The filling container can also be filled with shovels without any undue exertion on the part of the workman.

In consequence charging hoists or lowering of the machine are unnecessary.

In order to prevent parts of the charge which is actually being mixed from getting into the container 23, protecting plates 32 may be arranged on both sides of the latter, i. e. so as to extend between container and drum. In accordance with Fig. 4, transverse partitions 33 may also be provided in the container 28, so as to divide it into spaces the sizes of which correspond to the particular mixing ratio of sand, cement and gravel. In order to permit of altering this ratio, a number of guides 34 may be provided, which enable different positions of the transverse partitions 33 to be obtained. Consequently these partitions afford the simplest possible means Jfor maintaining a uniform mixing ratio. Moreover, the container 23 can, if required, be mounted hingedly, detachably or pivotally.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is A concrete mixing machine comprising a drum, means Jfior rotating said drum about its horizontal axis, a stationary delivery chute projectingV into the interior of said drum, shovels upon said drum, saidY delivery chute having at its interior end a portion flared in both directions to form a hopper so as to receive the entire quantity of materials thrown oi by said shovels when in upper position, means on said delivery chute toV direct the material either toward the exterior of said drum or towards the interior and a illing box located inside said drum below said hopper portion of said chute so as to be shielded by said hopper portion to permit continuous operation of said drum.

In testimony whereof I aflix my signature.

` KARL PIEI-ILER. 

